Reducing the ionospheric dispersion for P-band spaceborne SAR images by stochastic parallel gradient descent algorithm

There has been an increasing interest in the use of spaceborne SAR for measuring forest biomass which requires the use of longer wavelengths for enhanced foliage penetration. However, the propagation characteristics of the wave will be seriously affected by the ionosphere, especially below P-band (500 MHz). In this paper, the ionospheric effects of the spaceborne SAR in range direction are theoretically analyzed. In order to correct those effects, a new method called Stochastic Parallel Gradient Descent (SPGD) algorithm which was already applied in adaptive optics is proposed, and the simulation results verify the effectiveness of this method.